A communication network allows nodes to communicate with other nodes. A communication network may comprise all or a portion of one or more of the following: a public switched telephone network (PSTN), a public or private data network, a local area network (LAN), a metropolitan area network (MAN), a wide area network (WAN), a local, regional, or global communication or computer network such as the Internet, a wireline or wireless network, an enterprise intranet, other suitable communication link, or any combination of any of the proceeding. A communication network may comprise an Optical Transport Network (OTN).
Information may be transmitted and received through an optical network by modulation of one or more wavelengths of light to encode the information on the wavelength. In optical networking, a wavelength of light may also be referred to as a channel. Each channel may be configured to carry a certain amount of information through an optical network.
To increase the information carrying capabilities of an optical network, multiple signals transmitted at multiple channels may be combined into a single optical signal. The process of communicating information at multiple channels of a single optical signal is referred to in optics as wavelength division multiplexing (WDM). Without some form of WDM, the bandwidth in optical networks may be limited to the bit-rate of solely one wavelength. With more bandwidth, optical networks are capable of transmitting greater amounts of information.
The transmission of multiple traffic streams may result in inefficient use of network resources when the individual traffic bandwidth is less than the bandwidth of the transmitters and receivers in the network. In that case, each transmitter and receiver will have excess, unused bandwidth.